This invention relates generally to oscillators. Specifically, the present invention relates to oscillators capable of oscillation at any frequency within a wide range of frequencies. More specifically, the present invention relates to oscillators which are implemented with a minimum number of parts, and require only a minimum amount of power.
The oscillator of the present invention is useful in portable radios which require the transmission and receipt of signals over a wide range of frequencies. The present invention is suitable for applications requiring portability because the small number of parts allows the oscillator to be implemented in a small volume. The low power feature of the present invention makes it suitable for battery powered applications because it tends to allow the use of smaller, lower capacity batteries or extend the life of a given battery. However, the present invention is certainly not restricted to use in portable radios and may be advantageously used anywhere low power, a minimum number of parts, and a wide range of oscillation frequencies are needed.
Prior art oscillators have not effectively provided a solution for the problem of minimizing parts and power consumption while maximizing oscillation frequency and range. One prior art circuit requires the use of multiple voltage controlled oscillators (VCOs) to achieve a wide range of oscillation frequencies. This circuit provides an unsatisfactory result because too many parts are needed for its implementation. The excess number of parts further increases power consumption because each part tends to require power. Although this circuit achieves a required frequency range, it does so at the expense of power consumption and parts count.
Other prior art circuits use only one VCO and employ various frequency switching and adjustment techniques. These circuits also provide an unsatisfactory solution to the problem of minimizing power and parts count while maximizing the frequency range. The switching and adjustment techniques tend to require dedicated biasing circuits which increase both the parts count and the power consumption. Furthermore, the parts typically used to implement a VCO which demonstrates a wide bandwidth are high power parts.
Another problem caused by prior art oscillators concerns the duplication of voltage regulation and output buffering circuits. Both voltage regulation and buffering circuits tend to use active parts which consume significant amounts of power. Thus, the duplication not only tends to increase the parts count, but it significantly increases power consumption.